SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5cb1f3dfd776f632597e36870b4db524dc629661418b09ee736dde6596fa4cd9' 
  AND token = 'dphvSXH1CTVEqMwXPPnI+rKfUoNJY10FL2fZC6E0Two=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}